A proteomic approch to study parathyroid glands

1Endocrinology and Metabolism, Environment and Endocrine and Nervous Systems High Technology Center for the Study of the Effects of Harmful Agents, University of Pisa, Pisa, Italy; 2Psychiatry, Neurobiology, Pharmacology and Biotechnology, Pisa, Italy.

The molecular basis of parathyroid tumorigenesis has increased greatly over the last years and the variety of described abnormalities suggests different genetic defects leading to dysfunction of parathyroid cells. Using a combined approach based on two-dimensional electrophoresis (2DE) and mass spectrometry (MS) we performed a comparative proteome analysis to examine the global changes of parathyroid adenoma tissues protein profile with respect to the normal parathyroid tissue.

Sixteen parathyroid adenomas were studied. Three normal parathyroid biopsies obtained from Italian normocalcemic patients were used as control. Adenoma and normal samples from parathyroid tissue were compared by 2DE. Silver staining of 2DE gels detected 1293±110 and 1122±238 protein spots within a pH range from 3 to 10 from normal and adenoma parathyroid tissue respectively. By computational 2D gel image comparison, a total of 37 protein spots were found to be differentially expressed each exhibiting ≥2 fold-change (either increase or decrease) of mean value spot intensity in the adenoma with respect to normal samples. Among these 32 spots were identified by mass spectrometry. Western blot analysis was used to validate the expression changes of some proteins (i.e. Calmodulin, BSpry, Erk2, CCT-5, Parvalbumin and Peroxiredoxin-1) in parathyroid adenoma with respect normal samples. Among the proteins identified, a variety of biological functions were noted including programmed death cell, electron transport, cell proliferation, response to biotic stimulus, catabolism, lipid metabolism, cell organisation and biogenesis and organogenesis, transport, protein metabolism, signal transduction and chaperon activities. Furthermore pathway analysis indicated that 14 of these proteins are involved in a Cellular Development, Cellular Growth and Proliferation, Renal and Urological System Development and Function-associated network based on current literature. Our results demonstrate that proteomic analysis of parathyroid tissue may be an useful tool to identify potential biomarkers implicated in parathyroid cancer progression.